success the weight idea has worked and she is now sitting on her undercart properly for the 1st time,Vic i weighed the model 1st it worked out at 1/3rd of the weight of the model as the ballast you will need,using lead sheet i weighed out what i needed divided in 1/2 and then cut it into thin strips,these were folded with pliers and put into the engine nacelles forward but behind the engines firewalls holding it in place with tremco glazing tape[a gum type material similar to plasticine] ,a 1/72nd aircraft will need 30g,15g each side,also you will find the main legs will take time to locate correctly as they tend to try to drop back too far to the tail coursing the tail to sit too low,it took me 3 go's to get this right,hope that helps,
Bob