2008 KTM SX50 SR. LOWERING & ADVENTURE SPRINGS

Hi. I need some help from someone that may have already doen this... My older son just moved up from this Sr. to a KTM SX65... Now my 7 year old who is very small has outgrown his PW50.. He loves the PW50 but he looks to big for it and when he hits jumps the bike looks like it is going to fall apart. I went to the track and had him on the Sr. I lowered the rear shock to the 2nd position and lowered the front tubes in the trees as far as they can go. It have a mild stack on the bike.. .635-.640.. He can't touch the ground so he doesnt like it. I can get around that but he throttles out of a turn and the thing does a donut and throws him off the bike.. He is just too light and small.... I have heard you can put adventure mini springs in it instead to make it mild but can't find the psrings listed on ebay or any of the KTM sites.. Do you just buy the springs and thats all.. Nothing else? Also I heard you can drill a 3rd shock mount position to lower it.. Has anyone done that and will it be ok without lowering the front? I've search front lowering kits and found nothing...

I know it would just be better to get a Jr. but i already have this one from my older son in great shape.. If I can lower it and then return it to stock height next season it would be great... If anyone knows especially about the milder springs please let me know.

Springs...

I would like to drop at least another 1.5"-2"... I'll probabaly shave the seat but there isn't much foam I don't think to shave...

The Springs I am talking about are in the clutch not the fork springs... I heard changing the washer stack to adventure psrings make the bike move with less throttle and alot milder for beginners...