There is a current thread for the Seagull AT-6 that might be informative.

http://www.rcuniverse.com/forum/m_9669263/tm.htm

It is a very good flier. I'd rate the flight to be docile while a little more demanding on landing, because it is a war bird and must land reasonably fast especially having no flaps, it then becomes a matter of managing it to avoid nosing over. For that reason, I opted not to go with the retracts and I'd suggest not using them on other than a hard surface runway.

The issue is simple. The stock struts and mounts are designed for a good bit of forward rake of the main gear. The retract wheel wells are however positioned for no forward rake of retracts. If one compared the Seagull to the CMP version, the CMP version locates the wheel wells fully forward so that the strut can have a bend in it to provide forward positioning of the wheels. On the Seagull version, retracts on a grass field in my opinion would be too tipsy.

Edit note: Pardon my ignorance, I didn't know there was a T-6A Texan and thought you were referring to the AT-6. I see it listed by Horizon. It is 75-90 size tricycle gear plane.