I had a little look at lunchtime to see what I could find. Of course all of this takes no account of weather and track conditions nor the possibility of tagging onto a faster rider and lapping faster than might have happened on their own. Still it's only for a matter of interest (and discussion).

2014

The only TT newcomer to complete either supersport race was Alan Bonner. His time of 1:19:28.165 in SSP TT 1 would have been good enough for 8th in the MGP Junior race. His time at the end of the third lap (0:59:36.073) would have got him 4th in the Newcomers A race run over three laps. He upped his game in the second supersport race and would have bettered his placings to 6th and 3rd with times of 1:18:28.740 and 0:59:26.779 respectively.

2013

Sam Wilson completed supersport TT race 1 in a time of 1:18:42.419 which would have given him an 8th place finish in the Junior MGP. It would have won him the newcomers A race.

2012

There were two supersport TT race 1 finishers, but no-one finished race 2. Jimmy Storrar (1:21:25.11) would have finished 9th in the Junior MGP and Gary Graves (1:25:50.39) would have finished 37th. Taking their times at the end of lap three and comparing them to the Newcomers A race results Jimmy Storrar (1:01:16.76) would have won and Gary Graves (1:04:48.33) would have finished 4th.

2011

There were 4 TT newcomers that finished both supersport races in 2011 - Dean Harrison (who had raced previously at the MGP), Robert Wilson, Dan Hegarty and Lee Vernon. The first supersport TT was run over only 3 laps so I have compared the times to the end of the third lap of the Junior MGP. All four competitors SSP TT race 1 times (only 3 laps) would have placed them first at the end of lap 3 of the Junior MGP. Their times would also have won them the Newcomers A race with the exception of Lee Vernon who would have finished 4th.

Their SSP TT race 2 times would have won all four of them the Junior MGP that year. Their times at the end of lap three would also have won them the Newcomers A race, again with the exception of Lee Vernon would would have been 4th.

2010

The 2010 Junior MGP was run over 1 lap. The newcomers A race was run over 4 laps. 8 TT newcomers finished the SSP TT race 1 and 6 of those also finished the SSP TT race 2.

In summary at the end of lap 1 of the SSP TT 1 (and assuming they were the only one slotted in to the Junior MGP results) the finishing positions would have been Hudson Kennaugh (5th), David Johnson (9th), Dan Cooper (also 9th), David Jones (a former MGP rider - 17th), Brandon Cretu (28th), Gary May (33rd), Martin Loicht (46th) and Takahiro Itami (55th).

Their positions in the newcomers A race after 4 laps would have been Hudson Kennaugh (1st), David Johnson (also 1st), Dan Cooper (3rd), David Jones (7th), Brandon Cretu (also 7th), Gary May (also 7th), Martin Loicht (9th) and Takahiro Itami (also 9th).

At the end of lap 1 of the SSP TT 2 (again assuming they were the only one slotted in to the Junior MGP results) the finishing positions would have been David Johnson (8th), Hudson Kennaugh (15th), Dan Cooper (17th), Brandon Cretu (28th), David Jones (29th), Martin Loicht (52nd) and Takahiro Itami (62nd).

Their positions in the newcomers A race after 4 laps would have been David Johnson (1st), Hudson Kennaugh (3rd), Dan Cooper (4th), Brandon Cretu (7th), David Jones (also 7th) and Takahiro Itami (10th).